Methods of performing vagal-induced asystole

ABSTRACT

A method for indirectly stimulating a vagus nerve of a patient includes the steps of positioning one or more electrodes in the vicinity of the vagus nerve and then actuating the electrode(s) to create an electrical field for stimulating the vagus nerve. Disclosed embodiments include positioning one or more electrodes in the esophagus, trachea, or jugular vein, on the neck of the patient, and combinations thereof.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a divisional of U.S. patent application Ser.No. 09/716,783, filed Nov. 20, 2000, which is a divisional of U.S.patent application Ser. No. 09/139,442, filed Aug. 25, 1998, nowallowed, which claims priority to U.S. Provisional Application SerialNo. 60/072,284, filed Jan. 23, 1998 and U.S. Provisional Application No.60/056,994, filed Aug. 26, 1997.

BACKGROUND OF THE INVENTION

[0002] Minimally invasive direct coronary artery bypass (MIDCAB)surgery, both via sternotomy and alternative incisions, is asubstantially revolutionary development in surgery for allowing bypasssurgery to be conducted on a beating heart. However, beating heartsurgery shows an undesirably higher rate of early graft failure thanconventional coronary artery bypass procedures using cardiopulmonarybypass and cardioplegia. The technical difficulty of sewing the coronaryartery anastomosis on a beating heart is likely an important factor inthis difference in outcome between the two techniques. Controlledintermittent asystole (CIA) during brief intervals required for placinganastomotic sutures is suitable for improving the precision of coronaryanastomoses performed on a beating heart and reducing graft failurewhile increasing ease of operation.

[0003] Cardiopulmonary bypass (CPB) and chemical arrest usingcardioplegia solutions have traditionally provided surgeons with optimaloperative conditions: hemodynamic control and cardiac quiescence. Thisoptimal field has contributed to technical success in increasinglycomplex cardiac surgical operations. However, there has been recentinterest in performing coronary artery bypass surgery without eithercomplete cardiopulmonary bypass or cardioplegia. The quality of thedistal anastomosis is a primary concern among cardiac surgeons whoobserve and perform coronary artery bypass graft (CABG) proceduresunaided by cardioplegic arrest and cardiopulmonary bypass. Coronaryartery bypass graft failure rates reported with minimally invasivedirect coronary artery bypass range from 3.8 to 8.9%, while traditionalCABG on CPB has a reported anastomotic failure rate of 0.12%. This mayreflect a difference in anastomotic precision between MIDCAB andCPB-aided CABG. Although the benefits of avoiding extracorporealcirculation and global cardioplegia in beating heart procedures areimportant, they do not outweigh the performance of an optimal coronaryanastomosis.

[0004] The key difference in the anastomotic results betweenconventional CABG and beating heart CABG is related to achievingelective asystole during construction of the distal anastomosis. Cardiacmotion can be minimized during MIDCAB procedures via pharmacologicbradycardia (adenosine, β blockade) and mechanical stabilization usingvarious devices. Although these techniques do improve operativeconditions, they only approximate the advantages of elective asystoleachieved with CPB and cardioplegia.

[0005] Applicants show that a state of controlled intermittent asystole(CIA) is produced off CPB, which provides a major advantage otherwisegained by cardioplegic arrest on CPB. In particular, CIA is achievedusing unilateral (or bilateral) vagus nerve stimulation coupled withpharmacologic suppression of electromechanical escape activity.

[0006] Applicants demonstrate that elective, controlled intermittentasystole is produced by vagus nerve stimulation after treatment with anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, or acalcium channel blocker, or combinations thereof.

BRIEF DESCRIPTION OF THE FIGURES

[0007]FIG. 1 Duration of asystole achieved during 60 second vagalstimulation. Lines connect the periods of asystole observed in thenon-drug treated and drug treated states in each experimental animal.Drug administration lengthened significantly the period of asystole.

[0008]FIG. 2. Representative left ventricular and aortic pressuretracings during 60 second vagal stimulation in the non-drug treated (A)and drug treated states (B). Dark and open arrows mark the initiationand termination of the vagal impulse, respectively. Before drugtreatment, a short pause followed by escape and bradycardia was observedduring the 60 second impulse. After drug treatment, prolonged asystoleoccurred during the 60 second impulse with return of mechanical functionafter termination. lvp—left ventricular pressure; aop—aortic pressure.

[0009]FIG. 3. Representative left ventricular and aortic pressuretracings during sequential 15 second vagal stimulations in the non-drugtreated (A) and drug treated states (B). Dark and open arrows mark theinitiation and termination of the vagal impulses, respectively. Beforedrug treatment, each 15 second stimulation produced a short pausefollowed by bradycardia, while after drug treatment, asystole lasted theduration of each 15 second stimulation. lvp—left ventricular pressure;aop—aortic pressure. Abbreviations and Definitions CABG Coronary arterybypass graft CIA Controlled intermittent asystole CPB Cardiopulmonarybypass MIDCAB Minimally invasive direct coronary artery bypass; intendedto include any CABG without the use of global cardioplegia; synonymouswith beating heart surgery, irrespective of incision

DETAILED DESCRIPTION OF THE INVENTION

[0010] Increased acetylcholine activity by acetylcholinesteraseinhibition and prevention of electromechanical escape activity byβ-adrenergic receptor and calcium channel blockade during vagalstimulation produces a marked potentiation of vagal-induced asystole anda means of achieving CIA. CIA achieved by pharmacologic potentiation ofvagal-induced asystole is a suitable technique to facilitate MIDCABoperations. In particular, anastomoses and other complex suturing isfacilitated during such controlled asystolic events, a readilyappreciated advantage in surgery involving minimally invasive directcoronary artery bypass operations on a beating heart. CIA might haveparticular advantages in partially or totally endoscopic CABG, andpossibly in percutaneous or surgical transmyocardial laserrevascularization.

[0011] The present invention provides a pharmaceutical composition,comprising an acetylcholinesterase inhibitor, a β-adrenergic receptorblocker, and a calcium channel blocker, said composition useful forperforming beating heart surgery. The invention also provides that thecomposition is useful for controlled intermittent asystole in minimallyinvasive direct coronary artery bypass surgery. The invention furtherprovides that the compositions can be administered in combination withvagus nerve stimulation. Vagus nerve stimulation can be achieved bydirect or indirect electrical stimulation.

[0012] In preferred independent embodiments, the acetylcholinesteraseinhibitor can be pyridostygmine bromide, the β-adrenergic receptorblocker can be propranolol hydrochloride, and the calcium channelblocker can be verapamil bromide.

[0013] The invention also provides a pharmaceutical composition,comprising an acetylcholinesterase inhibitor and a β-adrenergic receptorblocker, said composition useful for performing beating heart surgery.In preferred embodiments, the acetylcholinesterase inhibitor can bepyridostygmine bromide, and the β-adrenergic receptor blocker can bepropranolol hydrochloride. The invention also provides that thecomposition is useful for controlled intermittent asystole in minimallyinvasive direct coronary artery bypass surgery. The invention furtherprovides that the compositions can be administered in combination withvagus nerve stimulation. Vagus nerve stimulation can be achieved bydirect or indirect electrical stimulation.

[0014] The invention also provides a pharmaceutical composition,comprising an acetylcholinesterase inhibitor and a calcium channelblocker, said composition useful for performing beating heart surgery.In preferred embodiments, the acetylcholinesterase inhibitor can bepyridostygmine bromide, and the calcium channel blocker can be verapamilbromide. The invention also provides that the composition is useful forcontrolled intermittent asystole in minimally invasive direct coronaryartery bypass surgery. The invention further provides that thecompositions can be administered in combination with vagus nervestimulation. Vagus nerve stimulation can be achieved by direct orindirect electrical stimulation.

[0015] The principal challenge of beating heart CABG surgery has been torecreate the advantageous operative conditions of a quiescent operativefield provided during conventional CABG with CPB and cardioplegicarrest. A variety of pharmacologic manipulations and mechanicalstabilizing techniques assist in performing CABG off pump. Theseinterventions to date minimize, but do not eliminate, cardiac motion.The concept that a state of controlled intermittent asystole improvesthe conditions for construction of distal coronary artery bypassanastomosis in non-CPB assisted cases was demonstrated by applicant. CIAis defined as operator-initiated and controlled intervals of mechanicalcardiac standstill. These intervals may be timed to coincide withplacement of sutures in the anastomosis, after which normal cardiacrhythm and hemodynamics are restored while preparations are made for thenext successive stitch. Experiments reported by the applicant indicatethat the minor bradycardia known to be produced by vagus nervestimulation is dramatically augmented to function as anelectromechanical “on-off switch” by pharmalogical inhibition ofacetylcholinesterase and blockade of β-adrenergic receptors and calciumchannels. Controlled intermittent asystole may prove equally useful forCPB-assisted cardiac surgery without global cardioplegia.

[0016] The chronotropic effects of vagal nerve stimulation have beenwell described and typically produce an initial pause followed by a“vagal escape” beat and sustained bradycardia during continuous optimalstimulation of the vagus nerve. Cardiac responses to a 60 second vagalstimulation without adjunctive therapy achieved an average pause of 1.6seconds terminated by vagal escape beats with a 19% reduction in heartrate. Vagus nerve stimulation alone did not produce a controlled periodof asystole desired for CIA. In contrast, a triple pharmacologic regimenof e.g, pyridostigmine, propranolol and verapamil inhibited vagalescape, and allowed sustained periods of asystole lasting up to 60seconds and sequential asystoles of 15 seconds each. Sequentialasystoles had no significant hemodynamic consequences.

[0017] It is apparent that suppression of the electromechanical escapeduring vagal stimulation is necessary to produce a sufficient intervalof asystole to allow a single stitch to be reliably placed duringconstruction of a distal CABG anastomosis. The negative chronotropiceffects of vagal stimulation are produced by acetylcholine release.Acetylcholine activity may be enhanced by inhibition ofacetylcholinesterase activity by agents such as pyridostigmine.Additionally, it is known that calcium channel blockade by e.g.verapamil potentiates the negative chronotropic effect of vagus nervestimulation. Another component in electromechanical escape may berelated to increased catecholamine activity in the sympathetic nervoussystem, triggered by hypotension. Catecholamines increase the rate ofdiastolic depolarization and decrease the threshold potential.β-adrenergic receptor blockade via e.g. propranolol reduces the effectsof catecholamine activity and facilitates suppression ofelectromechanical escape.

[0018] Administration of this combination therapy produced a significantreduction in heart rate and maximum developed ventricular pressure alongwith an increase in left ventricular end-diastolic pressure, but did notalter mean arterial pressure. There was no apparent fatigue of thispharmacologic effect after sequential stimulations. The animals used forpilot experiments appeared to tolerate this pharmacologic regimenwithout other adverse hemodynamic side effects, such as acidosis.

[0019] The short-term hemodynamic effects of a single prolongedstimulation were found to be substantially insignificant. Likewise themetabolic consequences as detected by pH and changes in base deficitwere insignificant.

[0020] The pharmacologic regimen used in this investigation sustainedthe period of vagal-induced asystole for about sixty seconds. Thisinterval would allow more than sufficient time for construction of adistal CABG anastomosis. Animals followed for two hours afteradministration of drugs displayed responses to vagal stimulation similarto those in the non-drug treated state, confirming reversibility of thedrug effects.

[0021] An untoward effect of the pharmacologic regimen which requiresconsideration before clinical application is vagal-induced secretions.All animals displayed significant salivation after initiation of vagalstimulation. However, there were no problems with oxygenation andventilation due to tracheobronchial secretions in these experiments.Vagal-induced oropharyngeal and tracheobronchial secretions arepertinent in the clinical setting. Additionally, the effects onrecurrent laryngeal nerve function require consideration.

[0022] Evidence suggests that the long-term effects of this regimen onthe vagus nerve are not harmful. Chronic vagus nerve stimulation hasbeen utilized as therapy for intractable seizure disorders withoutapparent nerve injury or impaired function. Applicants have shown thatvagal-mediated chronotropic control at two hours after completion of theexperimental protocol was similar to the non-drug treated state.

[0023] In summary, controlled intermittent asystole can be achieved bypotentiation of vagal-induced asystole via a pharmacologic combinationof e.g, propranolol and verapamil for suppression of electromechanicalescape and e.g, pyridostigmine for acetylcholinesterase inhibition.Asystole can be reproducibly achieved for prolonged intervals and forshorter multiple sequential intervals using this technique.

[0024] Nerve Stimulation

[0025] To achieve consistent asystole, applicants have found that nervestimulation of the right vagus nerve before or after treatment with thepharmacological combinations of the present invention is preferred.

[0026] Electrical stimulation is carried out on the right vagus nerve,preferably at a site on the neck. Other suitable locations for vagusnerve stimulation include, but are not limited to, unipolar or bipolarelectrical stimulation of the right or left vagus, or both, stimulationof the vagus in the chest after sternotomy, stimulation with apercutaneous catheter or electrode probe in the internal jugular vein,esophagus, or trachea, or combination of these. The nerve stimulator istypically a Grass wire with a single point of contact, but othersuitable stimulators include a pair of pacing wires or electrodes placedabout 1 cm apart to allow bipolar prodromic stimulation. A singlecontinuous impulse is applied of between about 5 seconds to about 90seconds, preferably between about 5 seconds and about 15 seconds, toallow a single stitch during surgery. Impulse parameters can readily bevaried, e.g, a frequency range of between about 1 Hz and about 500 Hz,preferably between about 20 Hz to about 80 Hz, more preferably about 40Hz, with an amplitude between about 1 to about 40 volts.

[0027] Pharmacologic Potentiation

[0028] The acetylcholinesterase inhibitor is also known as acholinesterase inhibitor. Suitable acetylcholinesterase inhibitorsinclude, but are not limited to tacrine hydrochloride, pyridostigminebromide, neostigmine methylsulfate, and edrophonium chloride. Onepreferred acetylcholinesterase inhibitor is pyridostigmine bromide.Acetylcholinesterase inhibitors are administered in a dosage rangebetween about 0.01 mg/kg and about 100 mg/kg, preferably between about0.1 mg/kg and about 2.0 mg/kg, more preferably about 0.5 mg/kg.

[0029] The beta-adrenergic receptor blocker is also known as abeta-adrenergic blocking agent. Suitable beta-adrenergic receptorblockers include, but are not limited to, sotalol HCl, timolol maleate,esmolol hydrochloride, carteolol hydrochloride, propranololhydrochloride, betaxolol hydrochloride, penbutolol sulfate, metoprololtartrate, acetbutolol hydrochloride, the combination of atenolol andchlorthalidone, metoprolol succinate, pindolol, and bisoprolol fumarate.One preferred beta-adrenergic receptor blocker is propranololhydrochloride. Beta-adrenergic receptor blockers are administered in adosage range between about 0.01 mg/kg and about 100 mg/kg, preferablybetween about 0.1 mg/kg and about 2.0 mg/kg, more preferably about 80μg/kg.

[0030] Suitable calcium channel blockers include, but are not limitedto, nifedipine, nicardipine hydrochloride, diltiazem HCl, isradipine,verapamil hydrochloride, nimodinpine, amlodipine besylate, felodipine,bepridil hydrochloride, and nisoldipine. One prefererred calcium channelblocker is verapamil hydrochloride. Calcium channel blockers areadministered in a dosage range of between about 0.001 mg/kg to about 1mg/kg, preferably between about 0.01 mg/kg and about 0.2 mg/kg, morepreferably about 50 μg/kg.

[0031] It will be understood that other dosage combinations may beeffective. The appropriate dosage is determined by the age, weight, sex,health status of the patient, and may vary with a variety of otherfactors according to conventional clinical practice.

EXAMPLE 1

[0032] Experimental Preparation

[0033] The sheep in the examples of the present invention receivedhumane care in compliance with “Principles of Laboratory Animal Care”formulated by the National Society for Medical Research and the “Guidefor Care and Use of Laboratory Animals” prepared by the National Academyof Sciences and published by the National Institutes of Health (NIHPublication No. 80-23, revised 1985). The experimental protocol wasapproved by the Institutional Animal Care and Use Committee of EmoryUniversity.

[0034] Seven sheep weighing 44 to 45 kg were premedicated with xylazine(0.1 mg/kg) and atropine (0.2 mg/kg) 30 minutes prior to induction ofanesthesia with intravenous thiopental (2.2 mg/kg) and lidocaine (2.2mg/kg). The animals were endotracheally intubated and placed on a volumeventilator with isoflurane for maintenance of anesthesia. Limb leads andprecordial lead were placed for electrocardiographic monitoring. Theright femoral artery was cannulated for arterial pressure and arterialblood gas monitoring. Tidal volume was adjusted to 10 cc/kg and a rateof 12 breaths per minute, with adjustments made to maintain pH at7.35-7.45, pO2 greater than 100 mm Hg, and pCO2 between 35-45 mm Hg.

[0035] A right cervical incision was performed, the vagus nerve wascarefully isolated, and a nerve stimulation probe (Harvard Apparatus,South Natick, Mass.) was placed on the nerve. A median sternotomy wasmade to expose the heart. A high-fidelity solid-state micromanometer(Millar Inc, Houston, Tex.) was secured in the ascending aorta foraortic blood pressure monitoring. An additional micromanometer wasintroduced into the left ventricle through the apex for left ventricularpressure monitoring.

EXAMPLE 2

[0036] Experimental Protocol

[0037] Each animal underwent vagal stimulation before and after drugadministration. The pharmacologic regimen consisted of pyridostigmine(0.5 mg/kg) for acetylcholinesterase inhibition, propranolol (80 μg/kg)for β-adrenergic receptor blockade, and verapamil (50 μg/kg) for calciumchannel blockade. Vagal stimulation was performed with a nervestimulator (Grass Instrument Co, Quincy, Mass.) in the monopolar mode ata frequency of 40 Hz, an impulse duration of 0.4 msec, and an amplitudeof 2-6 volts. Vagal stimulations were delivered in two regiments: 1)continuous 60 second impulse and 2) sequential 15 second impulses. Thecontinuous 60 second stimulation was designed to determine the longevityof vagal-induced asystole and the physiologic effects of prolongedvagal-induced hypotension. Sequential 15 second vagal stimulations wereperformed to simulate the suturing intervals required for graftanastomoses and to determine whether cardiac fatigue, electromechanicalescape, and physiologic effects occurred under these practicalconditions.

EXAMPLE 3

[0038] Data Acquisition and Analysis

[0039] Electrocardiographic and hemodynamic data were gathered via ananalog-to-digital conversion board (Data Translation, Inc, Marlboro,Mass.) and processed, stored, and analyzed via a microprocessor personal486 computer (Compaq Computer Corp, Houston, Tex.) using interactiveproprietary software (Spectrum™, Triton Technology, San Diego, Calif.).The system was configured to collect 4 channels of physiologic data at afrequency of 50 Hz (sufficient for slow-wave waveforms and mean pressuredata) over a 200 second period that encompassed the 60 secondstimulation or the sequential 15 second train of stimulations. Thesoftware allowed subsequent videographic display and analysis of thehemodynamic data.

EXAMPLE 4

[0040] Results

[0041] Before drug administration, vagal stimulation for 60 secondsproduced a brief pause in electromechanical activity (1.6±0.9 seconds)followed by vagal escape and resumption of sinus rhythm with a reductionin heart rate by 19.4±11.9% compared to pre-stimulation heart rate.Similarly, sequential 15 second vagal stimulation performed to stimulatethe suturing intervals required for CABG anastomoses produced a shortpause (1.1±0.4 seconds) followed by vagal escape and sinus rhythm with areduction in heart rate of 37±6%.

[0042] Administration of the pharmacologic regimen (propranolol,verapamil, pyridostigmine) reduced the heart rate and increased the leftventricular end diastolic pressure, but did not affect the mean arterialpressure or maximum dP/dt as shown in Table 1. TABLE 1 Hemodynamicsbefore and after drug treatment Before drugs After drugs p value (mean ±SEM) (mean ± SEM) (paired t test) Heart rate (bpm) 114 ± 4  87 ± 4 0.002MAP (mm Hg) 84 ± 5 84 ± 5 NS dP/dt max (mm Hg/sec) 3286 ± 232 2847 ± 140NS LVEDP (mm HG)  3.9 ± 0.5  7.3 ± 0.9 0.005

[0043] After drug administration, 60 second vagal stimulation producedasystole averaging 52±5.6 seconds. The individual responses of theanimals before and after drug administration are shown in FIG. 1. Sixanimals achieved controlled asystole. Five of these six achievedcontrolled asystole for greater than 50 seconds. The effects of 60second vagal stimulation before and after drug treatment in responsiveanimals are contrasted by representative left ventricular and aorticpressure tracings are shown for a representative experiment in FIG. 2.Before drug regimen treated, vagal stimulation produced no appreciablechange in cardiac rhythm or hemodynamics. In contrast, the triple drugregimen facilitated a consistent asystole and circulatory arrest untilthe stimulus was withdrawn, after which hemodynamics were rapidlyrestored to pre-stimulation values. The prolonged asystole andcirculatory arrest produced no significant differences in thehemodynamic parameters measured before and after drug-aided 60 secondvagal stimulation (Table 2). TABLE 2 Hemodynamics pre- and post-asystoleproduced by 60 second stimulation after drug treatment Pre-asystolePost-asystole p value (mean ± SEM) (mean ± SEM) (paired t test) Heartrate bpm) 91 ± 8 87 ± 7 NS MAP (mm Hg) 86 ± 6 92 ± 6 NS dP/dt max (mmHg/sec) 3032 ± 182 3223 ± 212 NS LVEDP (mmHg)  5.8 ± 1.0  6.0 ± 0.8 NS

[0044] Likewise there was no difference in the parameters measured byarterial blood gases at one and five minutes after the 60 secondstimulation compared to pre-stimulation values (Table 3). TABLE 3Arterial blood gas data pre-, 1 minute post-, and 5 minutes post-systoleproduced by 60 second stimulation after drug treatment Post-asystolePre-asystole 1 minute 5 minutes p p value (mean ± SEM) (mean ± SEM)(mean ± SEM) (ANOVA) pH 7.42 ± 0.03 7.40 ± 0.03 7.42 ± 0.03 NS PCO₂ 41 ±4  42 ± 4  40 ± 4  NS (mm Hg) PO₂ 377 ± 87  380 ± 75  390 ± 83  NS (mmHg) HCO₃ 26 ± 1  26 ± 1  26 ± 1  NS (mEq/L) Base 1.2 ± 0.7 1.0 ± 0.4 1.3± 0.5 NS excess (mEq/L)

[0045] ANOVA—one-way analysis of variance with repeated measures; NS—notsignificant; SEM—standard error of the mean.

[0046] Five to six sequential 15 second vagal stimulations in the drugtreated state produced consistent and stable asystole (FIG. 3). Three ofthe six animals had a single escape beat during one of the 15 secondstimulations. The other three displayed complete asystole during each ofthe 15 second stimulations. A sustained cardiac rhythm began an averageof 5.3±1.8 seconds after termination of each 15 second impulse duringwhich interval a single beat was often observed immediately afterwithdrawal of stimulation.

[0047] While the foregoing specification teaches the principles of thepresent invention, with examples provided for the purpose ofillustration, it will be understood that the practice of the inventionencompasses all of the usual variations, adaptations, and modifications,as come within the scope of the following claims and its equivalents.

What is claimed is:
 1. A method of performing vagal-induced asystole ina patient comprising the steps of: administering an amount of apharmaceutical composition effective to produce cardiac asystole uponstimulation of one or both vagus nerves; inserting an electrode into theesophagus of said patient; and actuating said electrode to create anelectrical field effective to stimulate said vagus nerve.
 2. The methodof claim 1, wherein said step of inserting an electrode into theesophagus of said patient comprises the step of inserting a firstelectrode into the esophagus of said patient; wherein said methodcomprises the further step of inserting a second electrode into theesophagus of said patient in spaced apart relation to said firstelectrode; and wherein said step of actuating said electrode to createan electrical field comprises the step of actuating at least one of saidfirst and second electrodes to create an electrical field.
 3. The methodof claim 2, wherein said step of inserting a second electrode into theesophagus of said patient in spaced apart relation to said firstelectrode comprises the step of inserting a second electrode into theesophagus of said patient approximately one centimeter from said firstelectrode.
 4. The method of claim 2, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of actuating both of said first and second electrodes to create anelectrical field.
 5. The method of claim 2, wherein said step ofactuating at least one of said electrodes to create an electrical fieldcomprises the step of actuating one or both of said electrodes in one ofa unipolar or a bipolar mode.
 6. The method of claim 1, wherein saidvagus nerve is stimulated for a period of between about five and aboutninety seconds.
 7. The method of claim 6, wherein said vagus nerve isstimulated for a period of between about five and about fifteen seconds.8. The method of claim 1, wherein said step of actuating said electrodeto create an electrical field comprises the step of applying an impulseat a frequency of between about one Hertz and about five hundred Hertz.9. The method of claim 8, wherein said step of applying an impulse at afrequency of between about one Hertz and about five hundred Hertzcomprises the step of applying an impulse at a frequency of betweenabout twenty Hertz and about eighty Hertz.
 10. The method of claim 9,wherein said step of applying an impulse at a frequency of between abouttwenty Hertz and about eighty Hertz comprises the step of applying animpulse at a frequency of about forty Hertz.
 11. The method of claim 1,wherein said step of actuating said electrode to create an electricalfield comprises the step of actuating said electrode to generateelectrical impulses having a duration of 0.4 msec.
 12. The method ofclaim 1, wherein said step of actuating said electrode to create anelectrical field comprises the step of transmitting to said electrode anelectrical impulse having an amplitude of from about one to about fortyvolts.
 13. The method of claim 12, wherein said step of actuating saidelectrode to create an electrical field comprises the step oftransmitting to said electrode an electrical impulse having an amplitudeof from about two to about six volts.
 14. The method of claim 1, whereinsaid vagus nerve is stimulated during a surgical procedure selected fromthe group consisting of: minimally invasive direct coronary arterybypass graft surgery, off-pump coronary artery bypass graft surgery,coronary artery bypass surgery performed on cardiopulmonary bypass,partially or totally endoscopic coronary artery bypass graft surgery,percutaneous or surgical transmyocardial laser revascularizationprocedure, or a surgical procedure performed upon a heart, heart valves,myocardium, coronary vascular structure, peripheral vascular structure,a electrophysiological procedure, a neurosurgical procedure, or apercutaneous transcatheter coronary procedure.
 15. The method of claim1, wherein said step of actuating said electrode to create an electricalfield effective to stimulate said vagus nerve comprises the step ofcreating an electrical field effective to stimulate said vagus nerve toachieve asystole.
 16. The method of claim 1, wherein the pharmaceuticalcomposition comprises an acetylcholinesterase inhibitor, a β-adrenergicreceptor blocker, and a calcium channel blocker.
 17. The method of claim1, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor and a β-adrenergic receptor blocker. 18.The method of claim 1, wherein the pharmaceutical composition comprisesan acetylcholinesterase inhibitor and a calcium charnel blocker.
 19. Amethod of performing vagal-induced asystole in a patient comprising thesteps of: administering an amount of a pharmaceutical compositioneffective to produce cardiac asystole upon stimulation of one or bothvagus nerves; inserting an electrode into the trachea of said patient;and actuating said electrode to create an electrical field effective tostimulate said vagus nerve.
 20. The method of claim 19, wherein saidstep of inserting an electrode into the trachea of said patientcomprises the step of inserting a first electrode into the trachea ofsaid patient; wherein said method comprises the further step ofinserting a second electrode into the trachea of said patient in spacedapart relation to said first electrode; and wherein said step ofactuating said electrode to create an electrical field comprises thestep of actuating at least one of said first and second electrodes tocreate an electrical field.
 21. The method of claim 20, wherein saidstep of inserting a second electrode into the trachea of said patient inspaced apart relation to said first electrode comprises the step ofinserting a second electrode into the trachea of said patientapproximately one centimeter from said first electrode.
 22. The methodof claim 21, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of actuatingboth of said first and second electrodes to create an electrical field.23. The method of claim 20, wherein said step of actuating at least oneof said electrodes to create an electrical field comprises the step ofactuating one or both of said electrodes in one of a unipolar or abipolar mode.
 24. The method of claim 19, wherein said vagus nerve isstimulated for a period of between about five and about ninety seconds.25. The method of claim 24, wherein said vagus nerve is stimulated for aperiod of between about five and about fifteen seconds.
 26. The methodof claim 19, wherein said step of actuating said electrode to create anelectrical field comprises the step of applying an impulse at afrequency of between about one Hertz and about five hundred Hertz. 27.The method of claim 26, wherein said step of applying an impulse at afrequency of between about one Hertz and about five hundred Hertzcomprises the step of applying an impulse at a frequency of betweenabout twenty Hertz and about eighty Hertz.
 28. The method of claim 27,wherein said step of applying an impulse at a frequency of between abouttwenty Hertz and about eighty Hertz comprises the step of applying animpulse at a frequency of about forty Hertz.
 29. The method of claim 19,wherein said step of actuating said electrode to create an electricalfield comprises the step of actuating said electrode to generateelectrical impulses having a duration of 0.4 msec.
 30. The method ofclaim 19, wherein said step of actuating said electrode to create anelectrical field comprises the step of transmitting to said electrode anelectrical impulse having an amplitude of from about one to about fortyvolts.
 31. The method of claim 30, wherein said step of actuating saidelectrode to create an electrical field comprises the step oftransmitting to said electrode an electrical impulse having an amplitudeof from about two to about six volts.
 32. The method of claim 19,wherein said vagus nerve is stimulated during a surgical procedureselected from the group consisting of: minimally invasive directcoronary artery bypass graft surgery, off-pump coronary artery bypassgraft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 33. Themethod of claim 19, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 34. The method of claim19, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 35. The method of claim 19, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 36. The method of claim 19, whereinthe pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.
 37. A method of performingvagal-induced asystole in a patient comprising the steps of:administering an amount of a pharmaceutical composition effective toproduce cardiac asystole upon stimulation of one or both vagus nerves;inserting an electrode into the jugular vein of said patient; andactuating said electrode to create an electrical field effective tostimulate said vagus nerve.
 38. The method of claim 37, wherein saidstep of inserting an electrode into the jugular vein of said patientcomprises the step of inserting a first electrode into the jugular veinof said patient; wherein said method comprises the further step ofinserting a second electrode into the jugular vein of said patient inspaced apart relation to said first electrode; and wherein said step ofactuating said electrode to create an electrical field comprises thestep of actuating at least one of said first and second electrodes tocreate an electrical field.
 39. The method of claim 38, wherein saidstep of inserting a second electrode into the jugular of said patient inspaced apart relation to said first electrode comprises the step ofinserting a second electrode into the jugular vein of said patientapproximately one centimeter from said first electrode.
 40. The methodof claim 38, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of actuatingboth of said first and second electrodes to create an electrical field.41. The method of claim 38, wherein said step of actuating at least oneof said electrodes to create an electrical field comprises the step ofactuating one or both of said electrodes in one of a unipolar or abipolar mode.
 42. The method of claim 37, wherein said vagus nerve isstimulated for a period of between about five and about ninety seconds.43. The method of claim 42, wherein said vagus nerve is stimulated for aperiod of between about five and about fifteen seconds.
 44. The methodof claim 37, wherein said step of actuating said electrode to create anelectrical field comprises the step of applying an impulse at afrequency of between about one Hertz and about five hundred Hertz. 45.The method of claim 44, wherein said step of applying an impulse at afrequency of between about one Hertz and about five hundred Hertzcomprises the step of applying an impulse at a frequency of betweenabout twenty Hertz and about eighty Hertz.
 46. The method of claim 45,wherein said step of applying an impulse at a frequency of between abouttwenty Hertz and about eighty Hertz comprises the step of applying animpulse at a frequency of about forty Hertz.
 47. The method of claim 37,wherein said step of actuating said electrode to create an electricalfield comprises the step of actuating said electrode to generateelectrical impulses having a duration of 0.4 msec.
 48. The method ofclaim 37, wherein said step of actuating said electrode to create anelectrical field comprises the step of transmitting to said electrode anelectrical impulse having an amplitude of from about one to about fortyvolts.
 49. The method of claim 48, wherein said step of actuating saidelectrode to create an electrical field comprises the step oftransmitting to said electrode an electrical impulse having an amplitudeof from about two to about six volts.
 50. The method of claim 37,wherein said vagus nerve is stimulated during a surgical procedureselected from the group consisting of: minimally invasive directcoronary artery bypass graft surgery, off-pump coronary artery bypassgraft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 51. Themethod of claim 37, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 52. The method of claim37, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 53. The method of claim 37, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 54. The method of claim 37, whereinthe pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.
 55. A method of performingvagal-induced asystole in a patient comprising the steps of:administering an amount of a pharmaceutical composition effective toproduce cardiac asystole upon stimulation of one or both vagus nerves;positioning an electrode on the neck of said patient; and actuating saidelectrode to create an electrical field effective to stimulate saidvagus nerve.
 56. The method of claim 55, wherein said step ofpositioning an electrode on the neck of said patient comprises the stepof positioning a first electrode on the neck of said patient; whereinsaid method comprises the further step of positioning a second electrodeon the neck of said patient in spaced apart relation to said firstelectrode; and wherein said step of actuating said electrode to createan electrical field comprises the step of actuating at least one of saidfirst and second electrodes to create an electrical field.
 57. Themethod of claim 56, wherein said step of positioning a second electrodeon the neck of said patient in spaced apart relation to said firstelectrode comprises the step of positioning a second electrode on theneck of said patient approximately one centimeter from said firstelectrode.
 58. The method of claim 56, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of actuating both of said first and second electrodes to create anelectrical field.
 59. The method of claim 56, wherein said step ofactuating at least one of said electrodes to create an electrical fieldcomprises the step of actuating one or both of said electrodes in one ofa unipolar or a bipolar mode.
 60. The method of claim 55, wherein saidvagus nerve is stimulated for a period of between about five and aboutninety seconds.
 61. The method of claim 60, wherein said vagus nerve isstimulated for a period of between about five and about fifteen seconds.62. The method of claim 55, wherein said step of actuating saidelectrode to create an electrical field comprises the step of applyingan impulse at a frequency of between about one Hertz and about fivehundred Hertz.
 63. The method of claim 62, wherein said step of applyingan impulse at a frequency of between about one Hertz and about fivehundred Hertz comprises the step of applying an impulse at a frequencyof between about twenty Hertz and about eighty Hertz.
 64. The method ofclaim 63, wherein said step of applying an impulse at a frequency ofbetween about twenty Hertz and about eighty Hertz comprises the step ofapplying an impulse at a frequency of about forty Hertz.
 65. The methodof claim 55, wherein said step of actuating said electrode to create anelectrical field comprises the step of actuating said electrode togenerate electrical impulses having a duration of 0.4 msec.
 66. Themethod of claim 55, wherein said step of actuating said electrode tocreate an electrical field comprises the step of transmitting to saidelectrode an electrical impulse having an amplitude of from about one toabout forty volts.
 67. The method of claim 66, wherein said step ofactuating said electrode to create an electrical field comprises thestep of transmitting to said electrode an electrical impulse having anamplitude of from about two to about six volts.
 68. The method of claim55, wherein said vagus nerve is stimulated during a surgical procedureselected from the group consisting of: minimally invasive directcoronary artery bypass graft surgery, off-pump coronary artery bypassgraft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 69. Themethod of claim 55, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 70. The method of claim55, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 71. The method of claim 55, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 72. The method of claim 55, whereinthe pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.
 73. A method of performingvagal-induced asystole in a patient comprising the steps of:administering an amount of a pharmaceutical composition effective toproduce cardiac asystole upon stimulation of one or both vagus nerves;inserting a first electrode into the esophagus of said patient;inserting a second electrode into the trachea of said patient; andactuating at least one of said electrodes to create an electrical fieldwhich stimulates said vagus nerve.
 74. The method of claim 73, whereinsaid step of inserting a second electrode into the trachea of saidpatient comprises the step of inserting a second electrode into thetrachea of said patient to a location approximately one centimeter fromsaid first electrode in said esophagus of said patient.
 75. The methodof claim 73, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of actuatingboth of said first and second electrodes to create an electrical field.76. The method of claim 73, wherein said step of actuating at least oneof said electrodes to create an electrical field comprises the step ofactuating one or both of said electrodes in one of a unipolar or abipolar mode.
 77. The method of claim 73, wherein said vagus nerve isstimulated for a period of between about five and about ninety seconds.78. The method of claim 77, wherein said vagus nerve is stimulated for aperiod of between about five and about fifteen seconds.
 79. The methodof claim 73, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of applyingan impulse to at least one of said electrodes at a frequency of betweenabout one Hertz and about five hundred Hertz.
 80. The method of claim79, wherein said step of applying an impulse at a frequency of betweenabout one Hertz and about five hundred Hertz comprises the step ofapplying an impulse at a frequency of between about twenty Hertz andabout eighty Hertz.
 81. The method of claim 80, wherein said step ofapplying an impulse at a frequency of between about twenty Hertz andabout eighty Hertz comprises the step of applying an impulse at afrequency of about forty Hertz.
 82. The method of claim 73, wherein saidstep of actuating at least one of said electrodes to create anelectrical field comprises the step of actuating at least one of saidelectrodes to generate electrical impulses having a duration of 0.4msec.
 83. The method of claim 73, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of transmitting to at least one of said electrodes an electricalimpulse having an amplitude of from about one to about forty volts. 84.The method of claim 83, wherein said step of actuating at least one ofsaid electrodes to create an electrical field comprises the step oftransmitting to at least one of said electrodes an electrical impulsehaving an amplitude of from about two to about six volts.
 85. The methodof claim 73, wherein said vagus nerve is stimulated during a surgicalprocedure selected from the group consisting of: minimally invasivedirect coronary artery bypass graft surgery, off-pump coronary arterybypass graft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 86. Themethod of claim 73, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 87. The method of claim73, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 88. The method of claim 73, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 89. The method of claim 73, whereinthe pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.
 90. A method of performingvagal-induced asystole in a patient comprising the steps of:administering an amount of a pharmaceutical composition effective toproduce cardiac asystole upon stimulation of one or both vagus nerves;inserting a first electrode into the esophagus of said patient;inserting a second electrode into a jugular vein of said patient; andactuating at least one of said electrodes to create an electrical fieldwhich stimulates said vagus nerve.
 91. The method of claim 90, whereinsaid step of inserting a second electrode into a jugular vein of saidpatient comprises the step of inserting a second electrode into ajugular vein of said patient to a location approximately one centimeterfrom said first electrode in said esophagus of said patient.
 92. Themethod of claim 90, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of actuatingboth of said first and second electrodes to create an electrical field.93. The method of claim 90, wherein said step of actuating at least oneof said electrodes to create an electrical field comprises the step ofactuating one or both of said electrodes in one of a unipolar or abipolar mode.
 94. The method of claim 90, wherein said vagus nerve isstimulated for a period of between about five and about ninety seconds.95. The method of claim 94, wherein said vagus nerve is stimulated for aperiod of between about five and about fifteen seconds.
 96. The methodof claim 90, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of applyingan impulse to at least one of said electrodes at a frequency of betweenabout one Hertz and about five hundred Hertz.
 97. The method of claim96, wherein said step of applying an impulse at a frequency of betweenabout one Hertz and about five hundred Hertz comprises the step ofapplying an impulse at a frequency of between about twenty Hertz andabout eighty Hertz.
 98. The method of claim 97, wherein said step ofapplying an impulse at a frequency of between about twenty Hertz andabout eighty Hertz comprises the step of applying an impulse at afrequency of about forty Hertz.
 99. The method of claim 90, wherein saidstep of actuating at least one of said electrodes to create anelectrical field comprises the step of actuating at least one of saidelectrodes to generate electrical impulses having a duration of 0.4msec.
 100. The method of claim 90, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of transmitting to at least one of said electrodes an electricalimpulse having an amplitude of from about one to about forty volts. 101.The method of claim 100, wherein said step of actuating at least one ofsaid electrodes to create an electrical field comprises the step oftransmitting to at least one of said electrodes an electrical impulsehaving an amplitude of from about two to about six volts.
 102. Themethod of claim 90, wherein said vagus nerve is stimulated during asurgical procedure selected from the group consisting of: minimallyinvasive direct coronary artery bypass graft surgery, off-pump coronaryartery bypass graft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 103. Themethod of claim 90, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 104. The method of claim90, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 105. The method of claim 90, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 106. The method of claim 90,wherein the pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.
 107. A method of performingvagal-induced asystole in a patient comprising the steps of:administering an amount of a pharmaceutical composition effective toproduce cardiac asystole upon stimulation of one or both vagus nerves;inserting a first electrode into the esophagus of said patient; placinga second electrode on the neck of said patient; and actuating at leastone of said electrodes to create an electrical field which stimulatessaid vagus nerve.
 108. The method of claim 107, wherein said step ofpositioning a second electrode on the neck of said patient comprises thestep of positioning a second electrode on the neck of said patient at alocation approximately one centimeter from said first electrode in saidesophagus of said patient.
 109. The method of claim 107, wherein saidstep of actuating at least one of said electrodes to create anelectrical field comprises the step of actuating both of said first andsecond electrodes to create an electrical field.
 110. The method ofclaim 107, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of actuatingone or both of said electrodes in one of a unipolar or a bipolar mode.111. The method of claim 107, wherein said vagus nerve is stimulated fora period of between about five and about ninety seconds.
 112. The methodof claim 111, wherein said vagus nerve is stimulated for a period ofbetween about five and about fifteen seconds.
 113. The method of claim107, wherein said step of actuating at least one of said electrodes tocreate an electrical field comprises the step of applying an impulse toat least one of said electrodes at a frequency of between about oneHertz and about five hundred Hertz.
 114. The method of claim 113,wherein said step of applying an impulse at a frequency of between aboutone Hertz and about five hundred Hertz comprises the step of applying animpulse at a frequency of between about twenty Hertz and about eightyHertz.
 115. The method of claim 114, wherein said step of applying animpulse at a frequency of between about twenty Hertz and about eightyHertz comprises the step of applying an impulse at a frequency of aboutforty Hertz.
 116. The method of claim 107, wherein said step ofactuating at least one of said electrodes to create an electrical fieldcomprises the step of actuating at least one of said electrodes togenerate electrical impulses having a duration of 0.4 msec.
 117. Themethod of claim 107, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step oftransmitting to at least one of said electrodes an electrical impulsehaving an amplitude of from about one to about forty volts.
 118. Themethod of claim 117, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step oftransmitting to at least one of said electrodes an electrical impulsehaving an amplitude of from about two to about six volts.
 119. Themethod of claim 107, wherein said vagus nerve is stimulated during asurgical procedure selected from the group consisting of: minimallyinvasive direct coronary artery bypass graft surgery, off-pump coronaryartery bypass graft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 120. Themethod of claim 107, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 121. The method of claim107, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 122. The method of claim 107, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 123. The method of claim 107,wherein the pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.
 124. A method of performingvagal-induced asystole in a patient comprising the steps of:administering an amount of a pharmaceutical composition effective toproduce cardiac asystole upon stimulation of one or both vagus nerves;inserting a first electrode into the trachea of said patient; insertinga second electrode into a jugular vein of said patient; and actuating atleast one of said electrodes to create an electrical field whichstimulates said vagus nerve.
 125. The method of claim 124, wherein saidstep of inserting a second electrode into a jugular vein of said patientcomprises the step of inserting a second electrode into a jugular veinof said patient to a location approximately one centimeter from saidfirst electrode in said trachea of said patient.
 126. The method ofclaim 124, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of actuatingboth of said first and second electrodes to create an electrical field.127. The method of claim 124, wherein said step of actuating at leastone of said electrodes to create an electrical field comprises the stepof actuating one or both of said electrodes in one of a unipolar or abipolar mode.
 128. The method of claim 124, wherein said vagus nerve isstimulated for a period of between about five and about ninety seconds.129. The method of claim 128, wherein said vagus nerve is stimulated fora period of between about five and about fifteen seconds.
 130. Themethod of claim 124, wherein said step of actuating at least one of saidelectrodes to create an electrical field comprises the step of applyingan impulse to at least one of said electrodes at a frequency of betweenabout one Hertz and about five hundred Hertz.
 131. The method of claim130, wherein said step of applying an impulse at a frequency of betweenabout one Hertz and about five hundred Hertz comprises the step ofapplying an impulse at a frequency of between about twenty Hertz andabout eighty Hertz.
 132. The method of claim 131, wherein said step ofapplying an impulse at a frequency of between about twenty Hertz andabout eighty Hertz comprises the step of applying an impulse at afrequency of about forty Hertz.
 133. The method of claim 124, whereinsaid step of actuating at least one of said electrodes to create anelectrical field comprises the step of actuating at least one of saidelectrodes to generate electrical impulses having a duration of 0.4msec.
 134. The method of claim 124, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of transmitting to at least one of said electrodes an electricalimpulse having an amplitude of from about one to about forty volts. 135.The method of claim 134, wherein said step of actuating at least one ofsaid electrodes to create an electrical field comprises the step oftransmitting to at least one of said electrodes an electrical impulsehaving an amplitude of from about two to about six volts.
 136. Themethod of claim 124, wherein said vagus nerve is stimulated during asurgical procedure selected from the group consisting of: minimallyinvasive direct coronary artery bypass graft surgery, off-pump coronaryartery bypass graft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 137. Themethod of claim 124, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 138. The method of claim124, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 139. The method of claim 124, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 140. The method of claim 124,wherein the pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.
 141. A method of performingvagal-induced asystole in a patient comprising the steps of:administering an amount of a pharmaceutical composition effective toproduce cardiac asystole upon stimulation of one or both vagus nerves;inserting a first electrode into the trachea of said patient; placing asecond electrode on the neck of said patient; and actuating at least oneof said electrodes to create an electrical field which stimulates saidvagus nerve.
 142. The method of claim 141, wherein said step ofpositioning a second electrode on the neck of said patient comprises thestep of positioning a second electrode on the neck of said patient at alocation approximately one centimeter from said first electrode in saidtrachea of said patient.
 143. The method of claim 141, wherein said stepof actuating at least one of said electrodes to create an electricalfield comprises the step of actuating both of said first and secondelectrodes to create an electrical field.
 144. The method of claim 141,wherein said step of actuating at least one of said electrodes to createan electrical field comprises the step of actuating one or both of saidelectrodes in one of a unipolar or a bipolar mode.
 145. The method ofclaim 141, wherein said vagus nerve is stimulated for a period ofbetween about five and about ninety seconds.
 146. The method of claim145, wherein said vagus nerve is stimulated for a period of betweenabout five and about fifteen seconds.
 147. The method of claim 141,wherein said step of actuating at least one of said electrodes to createan electrical field comprises the step of applying an impulse to atleast one of said electrodes at a frequency of between about one Hertzand about five hundred Hertz.
 148. The method of claim 147, wherein saidstep of applying an impulse at a frequency of between about one Hertzand about five hundred Hertz comprises the step of applying an impulseat a frequency of between about twenty Hertz and about eighty Hertz.149. The method of claim 148, wherein said step of applying an impulseat a frequency of between about twenty Hertz and about eighty Hertzcomprises the step of applying an impulse at a frequency of about fortyHertz.
 150. The method of claim 141, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of actuating at least one of said electrodes to generate electricalimpulses having a duration of 0.4 msec.
 151. The method of claim 141,wherein said step of actuating at least one of said electrodes to createan electrical field comprises the step of transmitting to at least oneof said electrodes an electrical impulse having an amplitude of fromabout one to about forty volts.
 152. The method of claim 151, whereinsaid step of actuating at least one of said electrodes to create anelectrical field comprises the step of transmitting to at least one ofsaid electrodes an electrical impulse having an amplitude of from abouttwo to about six volts.
 153. The method of claim 141, wherein said vagusnerve is stimulated during a surgical procedure selected from the groupconsisting of: minimally invasive direct coronary artery bypass graftsurgery, off-pump coronary artery bypass graft surgery, coronary arterybypass surgery performed on cardiopulmonary bypass, partially or totallyendoscopic coronary artery bypass graft surgery, percutaneous orsurgical transmyocardial laser revascularization procedure, or asurgical procedure performed upon a heart, heart valves, myocardium,coronary vascular structure, peripheral vascular structure, aelectrophysiological procedure, a neurosurgical procedure, or apercutaneous transcatheter coronary procedure.
 154. The method of claim141, wherein said step of actuating said electrode to create anelectrical field effective to stimulate said vagus nerve comprises thestep of creating an electrical field effective to stimulate said vagusnerve to achieve asystole.
 155. The method of claim 141, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitor,a β-adrenergic receptor blocker, and a calcium channel blocker.
 156. Themethod of claim 141, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor and a β-adrenergic receptor blocker. 157.The method of claim 141, wherein the pharmaceutical compositioncomprises an acetylcholinesterase inhibitor and a calcium channelblocker.
 158. A method of performing vagal-induced asystole in a patientcomprising the steps of: administering an amount of a pharmaceuticalcomposition effective to produce cardiac asystole upon stimulation ofone or both vagus nerves; inserting a first electrode into a jugularvein of said patient; placing a second electrode on the neck of saidpatient; and actuating at least one of said electrodes to create anelectrical field which stimulates said vagus nerve.
 159. The method ofclaim 158, wherein said step of positioning a second electrode on theneck of said patient comprises the step of positioning a secondelectrode on the neck of said patient at a location approximately onecentimeter from said first electrode in said jugular vein of saidpatient.
 160. The method of claim 158, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of actuating both of said first and second electrodes to create anelectrical field.
 161. The method of claim 158, wherein said step ofactuating at least one of said electrodes to create an electrical fieldcomprises the step of actuating one or both of said electrodes in one ofa unipolar or a bipolar mode.
 162. The method of claim 158, wherein saidvagus nerve is stimulated for a period of between about five and aboutninety seconds.
 163. The method of claim 162, wherein said vagus nerveis stimulated for a period of between about five and about fifteenseconds.
 164. The method of claim 158, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of applying an impulse to at least one of said electrodes at afrequency of between about one Hertz and about five hundred Hertz. 165.The method of claim 164, wherein said step of applying an impulse at afrequency of between about one Hertz and about five hundred Hertzcomprises the step of applying an impulse at a frequency of betweenabout twenty Hertz and about eighty Hertz.
 166. The method of claim 165,wherein said step of applying an impulse at a frequency of between abouttwenty Hertz and about eighty Hertz comprises the step of applying animpulse at a frequency of about forty Hertz.
 167. The method of claim158, wherein said step of actuating at least one of said electrodes tocreate an electrical field comprises the step of actuating at least oneof said electrodes to generate electrical impulses having a duration of0.4 msec.
 168. The method of claim 158, wherein said step of actuatingat least one of said electrodes to create an electrical field comprisesthe step of transmitting to at least one of said electrodes anelectrical impulse having an amplitude of from about one to about fortyvolts.
 169. The method of claim 168, wherein said step of actuating atleast one of said electrodes to create an electrical field comprises thestep of transmitting to at least one of said electrodes an electricalimpulse having an amplitude of from about two to about six volts. 170.The method of claim 158, wherein said vagus nerve is stimulated during asurgical procedure selected from the group consisting of: minimallyinvasive direct coronary artery bypass graft surgery, off-pump coronaryartery bypass graft surgery, coronary artery bypass surgery performed oncardiopulmonary bypass, partially or totally endoscopic coronary arterybypass graft surgery, percutaneous or surgical transmyocardial laserrevascularization procedure, or a surgical procedure performed upon aheart, heart valves, myocardium, coronary vascular structure, peripheralvascular structure, a electrophysiological procedure, a neurosurgicalprocedure, or a percutaneous transcatheter coronary procedure.
 171. Themethod of claim 158, wherein said step of actuating said electrode tocreate an electrical field effective to stimulate said vagus nervecomprises the step of creating an electrical field effective tostimulate said vagus nerve to achieve asystole.
 172. The method of claim158, wherein the pharmaceutical composition comprises anacetylcholinesterase inhibitor, a β-adrenergic receptor blocker, and acalcium channel blocker.
 173. The method of claim 158, wherein thepharmaceutical composition comprises an acetylcholinesterase inhibitorand a β-adrenergic receptor blocker.
 174. The method of claim 158,wherein the pharmaceutical composition comprises an acetylcholinesteraseinhibitor and a calcium channel blocker.